摘要
利用地统计学的方法 ,研究了科尔沁沙地甸子地不同土地利用方式草地和玉米地春季土壤含水量的空间变异规律。结果表明 ,草地表层、亚表层土壤含水量的变异函数均可很好地拟合成球状模型 ,具有明显的空间结构特征 ,其空间相关度分别为 0 979、0 999,变程分别为11 5 7m、19 4 1m ,分数维分别为 1 5 71、1 5 35 ,Moran’sI系数表现为在近距离内 (0 5～ 2 5m)为较强的正相关 (I=0 3～ 0 8) ,随着距离的增大 ,相关性变小 ,>5m后表现为较弱的负相关(I =0 2 )的变化趋势 ,克立格制图均表现出中央和四周高 ,西北角存在明显过渡带的空间分布格局 ,表层和亚表层具有很大的相似性。而耕地表层、亚表层土壤含水量变异函数分别拟合成线性和球状模型 ,其空间相关度分别为 0 344、0 914 ,变程分别为 7 6 7m、9 31m ,分数维分别为 1 92 8、1 6 81,Moran’sI系数分析和克立格制图表明表层、亚表层土壤含水量存在明显的差异。因此草地和耕地土壤含水量变异函数模型及参数、分数维、Moran’sI系数和克立格制图均存在明显的区别。同草地相比 ,玉米地土壤含水量空间格局特征表现为空间依赖性小 ,随机性大 ,空间自相关作用范围小 ,破碎化程度高。所以有必要采取退耕还草的措施来保护和恢复沙地生态系统的健康。
Spatial patterns of soil moisture for a grassland and an arable land in eastern Kerqin sandy land were studied by means of geostatistics. The results showed that soil rnoisture could be well expressed by a spherical model in grassland at both 0～10?cm and 10～20?cm layers. The spatial corelation coefficient, range and fractal dimension were 0.979 and 0.999, 11.57 m and 19.41 m, and 1.571 and 1.535 at 0～10 cm and 10～20 cm layers, respectively. In arable land, spherical and linier model could be expressed by semivariogram for soil moisture at 0～10 cm and 10～20 cm layers. The spatial correlation coefficient, range and fractal dimension were 0.344 and 0.914, 7.67 m and 9.31 m, 1.571 and 1.535 at 0～10 cm and 10～20 cm layers, respectively. Moran's Is and Kriging maps expressed the spatial structure characters in detail. Grassland had higher soil moisture content and spatial heterogeneity, closer spatial autorelation and dependence, and regular pattern, while arable land had lower soil moisture contents and spatial heterogeneity, looser spatial autorelation and dependence, and serious fragmentation (especially at 0～10 cm layer). Analysis indicated that agricultural cultivation might cause wind erosion, desertification and loss of productivity of sandy land. Therefore, the arable sandy land should be returned into grassland to conserve and restore the health of sandy land ecosystem.
出处
《生态学杂志》
CAS
CSCD
北大核心
2003年第6期43-48,共6页
Chinese Journal of Ecology
基金
国家科技攻关计划项目(2002BA517A11-5)
内蒙古自治区"十五"科技攻关资助项目(20010103)
